1. Field of the Invention
The present invention relates to a reaction type flame retardant and, more particularly, to an acrylophosphate derivatives.
2. Description of Related Art
Acrylophosphate flame-retardants are suitable for acrylic polymerization. The product retains its physical and chemical properties and can serve as a flame retardant.
Diphenyl-2-methacryloyloxyethyl phosphate is known as an acrylophosphate flame retardant. It has a high character residue test of 11% by TGA (Thermal Gravimetric Analyzer) at 600xc2x0 C.
The object of the present invention is to provide a new series of acrylophosphate derivatives. The present invention provides an acrylophosphate derivatives of the formula (I) 
wherein
nxe2x89xa71;
Ar is 
or 
The formula (I) acrylophosphate derivatives can be prepared by the following Scheme 1 or Scheme 2. 
The Scheme 1 comprises the following steps:
(1) heating bisphenol A or resorcinol, excess phosphoryl chloride and a predetermined amount of magnesium chloride as catalyst for carrying out a first stage esterification reaction to yield a intermediate of formula (II): 
wherein nxe2x89xa71, and n=1 as a main product;
(2) distilling and recovering the un-reacted phosphoryl chloride, adding a predetermined amount of ortho-alkyl-phenolic compound and an organic base, and heating for carrying out a second stage esterification reaction;
(3) after the completion of the second stage esterification reaction, adding further a predetermined amount of an acrylic compound for carrying out a third stage esterification reaction;
These three stages of esterification reaction are analyzed by 31P nuclear resonance spectroscopy for completing of reactions; and
(4) after substantial completion of said third stage of esterification reaction, adding an organic solvent, filtering out the hydrochloride salt of organic base, converting residual hydrochloride salt into ammonium chloride with a predetermined amount of ammonia gas; filtering off said ammonium chloride, and evaporating off said organic solvent from the filtrate under reduced pressure to thereby obtain a acrylophosphate derivatives. 
The Scheme 2 comprises the following steps:
(a) heating bisphenol A or resorcinol, excess phosphoryl chloride and a predetermined amount of magnesium chloride as catalyst for carrying out a first stage esterification reaction to yield a intermediate of formula (II): 
wherein nxe2x89xa71, and n=1 as a main product; and
(b) reacting said intermediate of formula (II) in step (a) with an acrylic compound, an organic base and an organic solvent to yield an acrylophosphate compound with four functional groups.
In the above two schemes, n is preferably 1, 2, or 3, and more preferably 1.
In the first stage of esterification reaction, the amount of said phosphoryl chloride is approximately 5 to 7 times by mole of said bisphenol A or resorcinol, and preferably 6 times; the amount of said magnesium chloride as the catalyst is approximately 0.1 to 1.0% by weight of said phosphoryl chloride, and preferably 0.4%; the organic base in step (2) is selected from the pyridine group, and the amount of said organic base is approximately 3 to 5 times by mole of said bisphenol A or resorcinol, and preferably 4 times; the amount of said ortho-alkyl-phenolic compound is approximately 1.8 to 2.0 times by mole of said bisphenol A or resorcinol; the amount of said acrylic compound added in step (3) is approximately 1.8 to 2.0 times by mole of said bisphenol A or resorcinol used in step (1); at least one of said organic solvents used in step (4) is selected from the group consisting of toluene, xylene, ethyl acetate, and butyl acetate; the organic base used in step (b) is triethylamine and its amount is 3.7 to 4.0 times by mole of said bisphenol A or resorcinol; and the amount of the acrylic compound used in step (b) is 3.7 to 4.0 times by mole of said bisphenol A or resorcinol; the organic solvent used in step (b) is selected from the group consisting of ether and dichloromethane.
The acrylophosphate derivatives of the present invention are prepared by a method with more detailed description: (1) Phosphoryl chloride, bisphenol A or resorcinol, and magnesium chloride were added to the reactor and heated at a temperature between 100xcx9c110xc2x0 C. for four hours; excessive phosphoryl chloride was then distilled; (2) an ortho-alkylphenolic compound and an organic base were then added and heated at a temperature between 110xcx9c120xc2x0 C. for one hour; (3) HEMA (2-hydroxyethylmethacrylate) was then added and heated at a temperature between 110xcx9c120xc2x0 C. for another hour; all three stages of the esterification reaction were measured for completion by 31P nuclear resonance spectroscopy; (4) after dissolving the product compounds into organic solvents, the organic base salts were filtered out first, and then a small amount of ammonia gas was used to convert the residual organic base salts to ammonium chloride; the ammonium chloride was filtered out and then the organic solvents were distilled for the purpose of purification.
According to the present invention, the preparation of phosphate containing acrylic functional group was performed in an one-pot reactor. Bisphenol A or resorcinol, excessive phosphoryl chloride and magnesium chloride as a catalyst were added in the reactor simultaneously. Condenser and temperature probes were set above the reactor, and a gas inlet was connected to the condenser for introducing the hydrochloride gas into the neutralization tank.
The heating temperature of the first stage of esterification reaction is at the range between 60 and 120xc2x0 C., and under normal pressure. The major product is a mono-substituted (n=1) compound, with a minor product of di-substituted (n=2) compound. The reaction scheme is as described in scheme (1); the preferable temperature is between 100 and 110xc2x0 C.; four hours later, distillation was carried out under reduced pressure (30xcx9c40 mmHg) to recover the excessive phosphoryl chloride; the phosphoryl chloride would cease to exist after two hours; the reaction temperature was cooled to room temperature; an equivalent of ortho-alkylphenolic compound and twice equivalents of the organic base were added for carrying out the second stage of esterification reaction; the reacting temperature was controlled in the range between 80 and 140xc2x0 C., preferably between 110 and 120xc2x0 C., for one hour; an equivalent of HEMA was then added to perform the third stage of esterification reaction; the reacting temperature was controlled between 70 and 140xc2x0 C., preferably between 110 and 120xc2x0 C., for one hour; all three stages of esterification reaction were measured for completion by 31P nuclear resonance spectroscopy.
After the completion of all reactions, the product compound was dissolved in organic solvents; the organic base salt was filtered out first and the residual hydrocloride salts of organic base were then converted to ammonium chloride with a small amount of ammonia gas; ammonium chloride is then filtered out and the organic solvent is recovered by distillation, and the acrylophosphate compound can be obtained.
After the completion of the first stage of esterification reaction and the recovery of phosphoryl chloride, organic base, solvents and four equivalents of HEMA can be added to prepare the acrylophosphate containing four functional groups, as described in scheme (2).